Consistently use RAND_bytes and check for failure.

RAND_pseudo_bytes just calls RAND_bytes now and only returns 0 or 1. Switch all
callers within the library call the new one and use the simpler failure check.
This fixes a few error checks that no longer work (< 0) and some missing ones.

Change-Id: Id51c79deec80075949f73fa1fbd7b76aac5570c6
Reviewed-on: https://boringssl-review.googlesource.com/2621
Reviewed-by: Adam Langley <agl@google.com>

crypto/cipher/e_aes.c

diff --git a/crypto/cipher/e_aes.c b/crypto/cipher/e_aes.c
index 64a0ee8..e4d3b8a 100644
--- a/crypto/cipher/e_aes.c
+++ b/crypto/cipher/e_aes.c
@@ -448,8 +448,7 @@
       if (arg) {
         memcpy(gctx->iv, ptr, arg);
       }
-      if (c->encrypt &&
-          RAND_pseudo_bytes(gctx->iv + arg, gctx->ivlen - arg) <= 0) {
+      if (c->encrypt && !RAND_bytes(gctx->iv + arg, gctx->ivlen - arg)) {
         return 0;
       }
       gctx->iv_gen = 1;